Friday, October 22, 2004

BANGKOK (Reuters) - The bird flu toll among tigers at a Thai zoo has risen to 83, but the keepers who looked after them are free of the deadly disease which has killed 31 people in southeast Asia this year, officials said on Friday.

The 57 keepers had been monitored closely for a week, two days longer than it takes for symptoms to appear, Charal Trinwuthingpong, a senior official on bird flu, told reporters.

But 51 tigers had to be put down in addition to 32 which died of the H5N1 bird flu from eating infected raw chicken at the Sri Racha Tiger Zoo, 80 km (50 miles) east of Bangkok.

"We had to perform mercy killings on those tigers because they were in critical conditions," said Preecha Ratanaporn of the Ministry of Natural Resources and Environment.

"We are monitoring four or five more of these tigers. If they show no symptoms in a week, we can declare the zoo free of bird flu," he said.

Thailand , the world's fourth largest chicken exporter until the outbreaks hit this year, has culled 60 million fowl since January to prevent the spread of the disease.

Health experts fear bird flu may mutate to become highly infectious in humans and unleash a global flu pandemic.

However, the World Health Organization said the deaths of the tigers had no implications for humans as tigers were not known to host the human influenza virus and thus be able to serve as a lethal genetic mixing vessel.

As many as 20 million people are believed to have died in the 1918-1919 Spanish flu outbreak which swept through a global population of humans who had little to no immunity.